The present invention relates to a switching IC (Integral Circuit) used in a power supply circuit or the like, and particularly to a technique effective for application to an improvement in the power generation efficiency by a DC/DC converter.
A frequency increase of a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) used in a power supply has recently been advanced to achieve a reduction in the size of a power supply circuit or the like and a high-speed load response.
A non-insulated DC/DC converter used in a power supply circuit of a personal computer, a computer game machine or the like in particular shows a tendency to make a large current and an increase in frequency with a demand for an increase in the current flowing into a CPU or the like to be driven, and size reductions of both a choke coil corresponding to a passive part and input/output capacitance, etc.
The non-insulated DC/DC converter has been widely used in the power supply circuit of the personal computer, the computer game machine or the like, for example. The non-insulated DC/DC converter needs to achieve an improvement in efficiency and a size reduction with an increase in current and a reduction in voltage with respect to a CPU or the like mounted in an electronic system.
The non-insulated DC/DC converter comprises a high side switch and a low side switch. The switches respectively make use of a power MOS-FET (Metal Oxide Semiconductor-Field Effect Transistor).
These switches perform voltage conversion by being alternately turned ON/OFF while the high side and the low side are being synchronized with each other. The high side switch is a switch for controlling a DC/DC converter, whereas the low side switch is a synchronous rectifying switch.
As a semiconductor device in which a power MOS-FET is sealed with a resin, there is known, for example, one in which a ground electrode terminal connected to a ground electrode formed by separation of a source electrode of a semiconductor chip is provided between a gate electrode terminal and a source electrode terminal, and gold wires or like low in impedance are used to connect among the respective source, gate and ground electrodes and their corresponding electrode terminals, thereby reducing noise of the semiconductor device when driven under a high-frequency operation (see, for example, the following patent document 1).
Patent Document 1
Japanese Unexamined Patent Publication No. 2002-009219